ljbad4life

There is more too it than that. With the Synergy system accessories like steering, braking, (as well as A/C) are electric. Coasting with the engine off in a non-hybrid car is dangerous. /Steve Sure, but one would that that not having to provide energy for moving the car but just to support steering, etc., pumps that a much smaller secondary (if not beefier primary) batter could be used charged of the alternator when the ICE is running. (No elec. motors, no regen braking, smaller sec. batt.) At least under stop/go city traffic this seems like it would be woth it - but maybe you're right, could be a slippery-slope toward a full hybrid. Still, avoiding the cost of an electric drivetrain while having an engine that could shut off seems worthwhile. But you must be right, as one would think that automakers would have gone in this direction. This system you are talking about is similar to the old "hybrid" vue models that were simply start and stop and a system made by Mercedes. The start and stop system can only be effectively used when stopped for a duration (at a stop light, not while rolling) and i will explain why; It takes time for a gas engine to start ( no matter how fast a company can get it this start time will always be there), that start lag(if you call it that) means that the car will have no propulsive power at all, which could lead to accidents. Current hybrids get around the "start time" with the use of an electric motor that can atleast provide some if not all the propulsive power until the ice can start up. Add to that the fact that these start, stop system really dont save more than 1-3% of fuel (proper maintaince will save you far more!) and the extra cost to that system with such miniscule savings there quite frankly isnt a point. Mercedes Benz has been sitting on there start/stop system for over 5 years now.